Inhibition of PARP 1 Protects Against Hyperglycemic-induced Neointimal Hyperplasia by Upregulating TFPI-2 Activity

To investigate the function and potential mechanism of PARP-1 poly(ADP-ribose) polymerase 1 (PARP1) in diabetic neointimal hyperplasia. Type 1 diabetes mellitus was induced using streptozotocin (STZ) in wild-type mice and PARP1-/- mice, and ligation of the left carotid artery was performed to induce neointimal hyperplasia. Ligated carotid arteries from diabetic mice developed more extensive neointimal hyperplasia and showed greater proliferation and migration than arteries from nondiabetic mice. The augmented remodeling response was absent in diabetic mice deficient in PARP1. PARP1 deficiency reduces diabetic neointimal hyperplasia by upregulating tissue factor pathway inhibitor (TFPI)-2, which acted as a suppressor of vascular smooth muscle cell (VSMCs) proliferation and migration. The underlying mechanisms involve PARP1 that acts as a negative transcription factor by enhancing TFPI-2 promoter DNA methylation. Our studies demonstrated for the first time that Inhibition of PARP1 alleviates neointimal hyperplasia in diabetes by up-regulating TFPI-2 expression and blocking VSMC proliferation and migration. The development of PARP1 inhibitors might serve to limit mainly proliferative and migratory processes in restenosis-prone diabetic patients HASMCs were treated with PARP-1 inhibitor PJ34 or PBS, and total RNA was purified with the RNeasy Mini Kit (Qiagen, Hilden, Germany). The concentration and purity were checked using a NanoDrop-1000 spectrophotometer (Thermo Fisher Scientific) and Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA). Biotin-labeled cRNA was synthesized using a Genechip 3 IVT PLUS Reagent Kit (Thermo Fisher Scientific). After fragmentation, each sample was hybridized onto a GeneChip™ Human Transcriptome 2.0 Array (Thermo Fisher Scientific). The procedure was conducted following the manufacturer s protocol. Statistical analysis was performed with the statistical software program R (ver. 2.7.2, 3.1.2). The CEL files were normalized using the DFW method (R ver. 2.7.2), and PCA was performed using R ver. 3.1.2. Using the Rank Products method (R ver. 3.1.2), probe sets that met the criterion of FDR < 0.05 were extracted as DEGs. Canonical pathway analysis of the DEGs was performed with Qiagen s Ingenuity Pathway Analysis (IPA, www.qiagen.com/ingenuity) (Qiagen). Pathways with p-value < 0.05 and |Z-score| 2 were extracted as being significantly regulated.